Microbiology Review/ Pneumonia and TB Flashcards
Bordatella Pertussis
“whooping cough”, highly contagious, spread by large droplets
gram neg, aerobic coccobacillus, capsulated
humans only reservoir
Clinical manifestation:
Catarrhal phase: rhinorrhea, lacrimation, conjunctival injection, low grade fever
Paroxysmal phase: uncontrollable expirations, followed by gasping inhalation, whooping cough
- convalescent phase: reduced frequency of cough
Complications: pneumonia
tx: azithromycin
Klebsiella Pneumonia
gram neg, nonmotile rod
- facultative anaerobe
seen in UTI, soft tissue infections, endocarditis, CNS infections, severe bronchopneumonia
CXR see cavitary lesions and the patients produce “currant jelly sputum”
Moraxella catarrhalis
gram negative, grows well on blood or chocolate agar
- diploccoi
- catalase and oxidase positive
- pneumonia commonly seen in the elderly, otitis media in children
Neisseria meningitidis
aerobic gram negative kidney shaped diplocci
- oxidase positive, grows on Thayer-Martin media and chocolate media
Seen in dorms/military barracks causing outbreak of meningitis (transmitted through close contact)
Also causes pneumonia
Tx: penicillin G, or 3rd generation cephalosporin
tx people in contact with rifampin
without tx 70-90% will die - this has a high mortality rate
morbidity: limb loss, hearing loss, long-term neurologic disability
Pseudomonas aeruginosa
aerobic-gram negative rod
- produces pyocyanin (blue-green pigment): fluorescent green sputum
- “nosocomial pathogen” picked up in hospital/nursing home
- this will grow anywhere: plants, counters, moist surfaces
Infections:
- HAP, VAP
- CA infections related to hot tubs
- most common cause of otitis externa, “swimmer’s ear”
- puncture wounds through tennis shoes
- Endocarditis, UTIs, skin infections
Bacterial Factors: its got them all!
- exotoxins, endotoxins, pili, flagella, proteases, capsule….. etc.
tx: broad spectrum Abs: always tx with two - extended spectrum penicillin and aminoglycoside (Levo and Gent) - trying to avoid resistance
Chlamydophila psittaci
gram negative, intracellular bacteria (phagocytsed by macrophages)
Disease:
Psittacosis: bird fancier’s pneumonia
- atypical pneumonias
- febrile illness
tx: tetracyclines, fluoroquinolones, macrolides
Chlamydophila pneumoniae
80% of adults are seropositive - and is common infection in children under five
- causes an atypical pneumonia with non-productive cough often preceded by nasal congestion, sore throat, hoarseness and h/a
tx: tetracyclines, macrolides, fluoroquinolones
CXR shows diffuse infiltrate, exam reveals crackles and ronchi in the lungs
what do you tx atypical pneumonia with?
levofloxacin, arithromycin, azithromycin
Coxiella burnetti
“Q fever”
- gram negative that is hosted in monocytes
- not completely eliminated after acute infection: will continue to multiply in IC patients and can cause endocarditis
- lives in mammals, birds and ticks
Major outbreaks: related to sheep and goats during lambing season
“Q fever” : 60% will fight off without disease, 38% will have self-limited disease, 2% will have more prolonged disease: pneumonia, hepatitis, rash, meningitis, encephalitis, pericarditis, myocarditis
- females can have chronic uterine infection –> spontaneous abortions
Q fever endocarditis = fever of unknown origin, see intermittent fever, vegetations are frequently absent, have cerebral emboli, renal insufficiency, splenomegaly, hepatomegaly (due to vegetations)
tx: doxycycline for 2 weeks in acute case, then use doxycycline + hydroxycholoquine (an anti-malarial that increases the pH), for 18-36 months for endocarditis
francisella tularensis
“tularemia” infectious zoonosis, small aerobic pleomorphic gram negative bacillus
- harbored in rabbits, squirrels and muskrats
- human acquired through contact with animal tissue, meat or bite of infected tick or deer fly
Clinical:
- ulceroglandular (fever, swollen lymph nodes, ulcer at the site, sore throat) presentation,
- glandular, (fever and constitutional syndromes)
- ocuoglandular,
- typhoidal, (just fever only)
- oropharyneal, (uncommon in US, affects mucus membranes of mouth = pharyngitis and pharyngeal ulcers)
- pneumonic (most serious, caused by inhalation exposure, fever, dry cough, substernal discomfort, peribronchial infiltrates, bronchopneumonia, hilar adenopathy)**
tx: gentamicin, doxycycline, ciprofloxacin
mortality is less than 1% if properly treated
bacillus anthraxis
- gram positive, non motile rob, aerobic, catalase positive, hemolysis negative
- grows on sheep agar
- zoonotic infection common in goats sheep, cattle, pigs, horses: related from meat wool, hides, bones, hair - soil contaminated with spores
clinical: inhalation manifestations
- “mediastinal widening”
- mediastinal adenopathy, pleural effusion, rapidly fatal if not tx with multiple anibiotics and pleural drainage*
- most commonly see cutaneous form
- GI sx, meningeal sx
tx: multi drug abs and pleural drainage, vaccination is available
prognosis: 45% mortality of inhalation in 2001, 20% mortality for untreated cutaneous lesions
Yersinia pestis
another zoonotic, coccobacillus, nonmotile, non spore forming
spread through rodents and fleas - prarie dogs are common host
clinical: patients have bubos (nodules), septicemia and pneumonia
Bubonic plague: swollen tender lymph nodes, closest to site of initial infection, fever, chills, body aches, h/a’s. if untreated develop confusion, delerium, convulsions
Septicemic plague: DIC, HTN, renal failure, ARDS type picture
Pneumonic Plague: highly fatal, die w/in 24 hours - see fever, cough, tachycardia, chills, hemoptysis, circulatory collapse
tx: streptomycin for pneumonic
tetracyclines for bubonic form
chloramphenicol for meningitis
Leptospirosis
- spirochete with terminal hook, use silver staining or dark field microscopy,
carried in rodents, dogs, pigs, cattle, sheep
- colonizes renal tubules and excreted in urine
transmission: penetrates the skin, mucus membranes and through contaminated water
Early phase: fever myalgia, h/a, nausea, vomiting, ab pain, conjunctival swelling
“Weil’s disease” = late manifestation - jaundice, hemorrhage, thrombocytopenia
ddx: via agglut test
tx: doxycycline or penicillin
H. influenza
encapsulated gram negative rod, aerobic or facultative anerobic - grows on chocolate agar: Factor X and Factor V
- used to cause epiglottis commonly in children, though now they are vaccinated (high fever, chills, sore throat - see thumb sign on CXR due to swollen epiglottis - though may be seen in unvaccinated children)
transmitted via resp. droplets, type B used to be most common cause of meningitis in children and otitis media
Clinical:
- Meningitis in children under 5 y/o (though not seen much more)
- epiglottitis is life threatening in children - fever, chills, dysphagia, drooling, respiratory distress with stridor (need to distinguish from croup, steeple sign on XRAY) - course is rapid
- pneumonia: fever, cough, lobar consolidation, smoking is a risk factor
- sinusititis, otitis media
tx: 3rd generation cephalosprin
- have vaccination for type B: Hib
tx people that come into contact with this with rifampin, used for prophylaxis
Corynebacterium diptheriae
- gram positive, “club shaped”, aerobic, grows on throat and pharynx of humans - diptheria forms a toxin that is transmitted via respiratory droplets
“Respiratory Diptheria” - sore throat, malaise, thick tonsilar exudate that is very sticky (don’t scrape it off) - “gray membrane”
“bull neck” huge cervical lymphadenopathy, develop stridor
- if membrane extends down over trachea it can lead to obstruction
tx: erythromycin and an antitoxin
prevention: vaccination - dTap
Legionella Pneumophilia
weakly gram negative, facultative intracelular
- “grows on charcoal yeast extract”
- grows in water, A/C systems and is transmitted through aerosols from these systems - no human/human transfer
risk factors: smoking, age greater than 55, alcohol intake
Pneumonia: fever, malaise, cough, chills, h/a, c/p, diarrhea
distinguished from other pneumonias due to “myalgias, h/as and diarrhea” also see mental confusion
- fever is elevated and lower than expected pulse
“pontiac fever” : fever, sore throat, myalgia, h/a, fatigue, short duration lasting on average 3 days
ddx: antigen urine test
tx: fluoroquinolones, azith, erythromycin + rifampin for IC patients (these are all used for atypical pneumonia)
mycoplasma pneumonia
smallest free living bacteria, no cell wall, cause of atypical pneumonia
- needs cholesterol for culture,
tranmitted through resp. droplets
- seen in atypical pneumonia in dormitory and military barracks:
**usually seen in young people: ages 5-20
pneumonia: fever, malaise, h/a, cough, “walking pneumonia” with nonproductive cough - sx will last 3-4 weeks
also causes bullous myringitis: blood filled tympanic membrane
ddx: positive cold agglutinins! usually made on clinical basis though
tx: macrolides (erythromycin, azithromycin, clarithromycin) or tetracyclines
will have IgM autoantibody that is directed against the antigen of RBC’s
streptococcus pneumonia
- most common CAP *
gram positive, dipplococci, lancet shaped, grows on blood agar plates, alpha hemolytic, optochin sensitivie - grows in upper respiratory tracts
- has a polysaccharide capsule
risk factors: influenza infection, COPD, CHF, alcoholism, asplenia - initially colonizes the nasopharynx is then aspirated –> pneumonia
“typical pneumonia”: most common cause, shaking chills, rigos, lobar consolidation, and “rusty blood tinged sputum”
Adult menintitis, otitis, sinusitis are other effects
tx: beta lactams, macrolides, fluoroquinolones
tx of meningitis: 3rd generation cephalosporin
Staphylococcus aureus
gram positive cocci in clusters, catalase and coagulase positive, beta hemolytic, grows in small yellow colonies on blood agar, ferments mannitol
common pathogen of nasal flora - 25% present in popluation - transmission through hands, sneezing, surgical wounds, contaminated food (potato salad, custards, canned meats)
- there are over 50 difft. virulence factors
3 toxin mediated diseases: staph food poisoning, staph TSS, staph scalded skin syndrome
Clinical manifestations:
- impetigo, folliculitis, furuncle, abscess, cellulitis, mastitis, nec. fascitis, wound infections
- bacteremia, endocarditis (roths spots, oslers nodes, janeway lesions, peticheai)
- pericarditis, osteomyelitis
pneumonia: nosocomial salmon colored sputum
Staph food poisoning: 2-6 hours after eating, nasuea, vomiting, diarrhea
TSS: due to TSST-1 super antigen: have fever, hypotension, desquamation of palms and soles
tx: gastroenteritis is self limiting - no tx
for non MRSA = tx with nafcillin/oxacillin
MRSA tx: Vancomycin
what do you treat MRSA with?
vancomycin
non drug resstant staph tx?
nafcillin/oxacillin
pneumocystis jirovecii (carinii)
- fungus that an obligate extracellular parasite, seen on silver stain, hat shaped
- opportunistic in HIV patients with CD4)
tx: sulfamethaxazole/trimethoprim (SMX/TMP= bactrim)
histoplasma capsulatum
fungi that is seen in the central US - its a facultative intracellular parasite found in RES (retic. endothelial) cells
- found in soil, caves, abandoned buildings with bird and bat guano”: spleunking, cleaning under bridges
transmission: through disruption of soil,
endemic to miss. river and ohio valley
ddx: silver stain with thin based budding yeast
presents with acute pulmonary syndrome: fevers, chills, fatigue, non prod, cough, anterior chest discomfort and myalgias
chronic pulmonary syndrome: progressive and often fatal, elderly, IC and COPD pts at most risk
xRAY: acute pneumonia with patchy lobar infiltrates
chronic see upper lobe infiltrates, cavities and fibrosis that mimics TB
Tx: Itraconazole, amphotericin B
Blastomyces dermatitidis
silver stain shows “broad based budding yeast” - thermally dimorphic fungus
- assoc. with soil and decaying vegetations
- endemic to north and south central and great lakes
acute pulmonary sx: fever, malasie non. prod. cough, CXR shows lobar, multilobar or nodular infiltrates and skin lesions
chronic pulmonary: fever, nigh sweats, cavitary lesions, fibrosis - CXR shows cavitary nodules
tx: all patients should be treated ! itraconazole in mild cases, severe cases in amphotericin B
Coccidiodes immitis
“valley fever” - dimorphic fungi, grows in south west US, endemic in desert areas- CA, NM, AZ
most pts are asymptomatic
pulmonary infection:
fever, w/l, fatigue, dry cough, pleuritic c/p, arthralgias, erythema nodosum, CXR shows pulmonary infiltrates, hilar adenopathy, pulmonary nodules that are vacitary
disseminated infection: HIV patients are at risk, pregnant patients
tx: itraconazole and ampotericin B
Stongyloides stercoralis
- endemic in warm climates world wide
transmission: through exposed skin with free living larvae living in contaminated soil, after larvae enter skin they go through circulation to pulmonary vasculature –> rupture alveolar spaces and are swallowed into GI tract. devleop into adult worms in upper part of SI. eggs hatch and larvae migrate to colon and are passed in feces
Can be severe in IC, resembles ARDS with acute onset of dysnpea , prod. cough, hypoxemia
tx: ivermectin
aspergillosis
found in soil, and decaying matter - grows a spore like conidia thats aerozolized, can be isolated from basements, bedding, humidifiers, marijuana (mold)
Invasive aspergillosis in IC:
- fever, pulmonary infiltrates, wedge-shaped densities resembling infarcts, sinusitis, CNS abscesses, osteomylitis, endocarditis
Chronic pulmonary aspergillosis:
- have ball like cavity in lung, can form in TB, hisoplasmosis or other previous cavitary lesions like sarcoidosis
Allergic Bronchopulmonary Aspergillosis - seen in chronic asthma patients of patients with CF, causes obstruction, eos, mucus plugs containing hyphae, elevated IgE levels, bronchiectasis (tx with corticosteroids/itraconazole)
ddx: via BAL, needle aspiration of aspergilloma, open lung biopsy
tx: antifungal - Voriconazole or liposomal amophotericin B
Cryptococcosis
due to crytococcus neoformans- occurs in IC: seen in HIV infection with CD4
tx: amphotericin B and flucytososine (if have AIDS, followed by fluconazole daily)
HACEK organisms
these are organisms causing endocarditis
Haemophilus spp Actinobacillus Cardiobacterium hominis Eikenella corrodens Kingella spp
%5 of endocarditis
encapsulated gram negative rod
H. influenza
gram positive encapsulated diplococci?
Strep. pneumonia
currant jelly sputum
klebsiella pneumonia
silver stain showing “hats”
pneumocystis jiroveci (carinii) = seen in AIDS patients with CD4 under 200
AC units in hx, bradycardia with high fever
legionella pneumonia
college students
mycoplasma pneumonia - see cold agglutinins
splenectomy/sickle cell disease
streptococcus pneumoniae
catbreeder
toxoplasmosis (toxoplasma ghondi)
homeless shelter
TB
cave explorer
histoplasmosis
elderly pneumonia
think E. Coli
diabetic abscess thats not treated with Abs?
mucor mycosis - fungus
positive methamine-silver stain of lung tissue
pneumocystis carinii
acid fast sputum stain?
test for TB
whooping cough?
bordatella pertussis
croup? “barking cough”, low grade fever, steeple sign on CXR
parainfluenza virus
epiglottitis, drooling, thumb sign seen on CXR?
H. influenza
neonatal patients with cough and CXR infiltrates?
RSV - seen in the very young
gram negative bacteria that grows on charcoal yeast extract?
whats the tx?
legionella - “legionaire’s disease”
tx: arithromycin
amphotericin B
tx of fungal infections
Bactrim DS - sulfamethoxozole/trimethorpirm
prophylactic against pneumocystis jirovecii
clindamycin treats?
used to tx anaerobes
methicillin/nafcillin treats?
used to tx staph
erythema nodosum, pneumonia, California?
Coccidiodes Immitis
- this is also seen in sarcoidosis
urine antigen test?
used to detect legionella
copious green sputum, gram negative bacillus, most common HAP?
pseudomonas aeruginosa
gram negative coccobacillary rod that if typable is encapsulated?
H. influenza
most common species of fungus to cause “fungus ball” in lungs is?
aspergillus
daycare, 4 months old, common respiratory infection in young infants?
RSV
kidney shaped gram negative diploccoci?
neisseria meningitidis (more common in college students/barracks)
TB drug resulting in eye complaint: difficulty with vision/spinning sensation
ethambutol
fever, night sweats, w/l, fatigue, cough, sputum, lower lobe pneumonia - lesions on skin and legs, wet mount shows broad based buds that are yeast like
blastomycosis - seen in Louisiana
upper lobe and cavitary
think TB
reading PPD test
5 mm: if pt. has HIV, recent close contact of TB case, organ transplants or immunosuppressed
10 mm: if pt works in hospitals, new arrivals to the country, injection drug users, people with clinical conditions (DM, leukemia, ESRD)
15 mm: if patient is part of general population, with very low risk of exposure
india ink stain of sputum
cryptococcus neoformans
CD4 count less than 50 and pneumonia?
think MAC
most common cause of post-influenza bacterial pneumonia?
staph aureus
Hanta Virus
- spread by deer mouse, rodents shed the virus through urine droppings and saliva
Incubation Period: 2-4 weeks
Febrile phase: Symptoms include fever, chills, sweaty palms, explosive diarrhea, malaise, headaches, nausea, abdominal pain, back pain, and SOB. Lasts 3-7 days
Hypotensive phase: Platelet levels drop, tachycardia, hypoxia
Oliguric phase: Lasts 3-7 days. Characterized by proteinuria and renal failure
Diuretic phase: Diuresis of 3-6 liters per day, which can last for a couple of days up to weeks.
Convalescent phase: This is normally when recover occurs and symptoms begin to improve.
what occurs below CD4 of 50?
MAC
intracellular pathogenic bacteria similar to rickettsia?
coxiella burnetti
organism without a cell wall
mycoplasma pneumonia
gram negative organisms that are “fastidious” and are rare cause of infective endocarditis - can be associated with dental carries
HACEK organisms:
Haemophilus Actiniobacillus actinomycetomemcomitans Cardiobacterium hominis Eikenella corrodens Kingella kingae
most common exacerbation of COPD infection?
moraxella catarrhalis - see gram negative diploccoi
A disorder that begins with a flu symptoms stage that resolves and comes back affecting the liver, lungs, and kidneys going to renal failure
leptospirosis - bacterial spirochetes
tachyzoites that stain with H and E staining
think toxplasma ghondi - think cats
toxoplasma encephalitis is most common in CNS infection in AIDS patients - see growing masses –> confusion and headaches
what is immune response to strep pneumonia?
humoral immunity will be seen with encapsulated organisms - patients with splenectomy will need to be immunized (antibody mediated pneumonia)
leptospirosis
seen with dogs, cat, livestok urine
long think spirochete thats tightly coiled
first phase = organism in blood nd CSF causes high spiking temp, h/a, severe mm. aches
second phase: see emergence of IgM and involves meningismus
Weil’s disease: see severe renal failure, hepatitis, jaundice, mental changes, hemorrhages
how does influenza virus change?
minor changes associated with antigenic drift - there are sudden changes from year to year
how does splenectomy affect immune system?
results in patient no longer having the ability to produce opsonizing IgG antibodies to encapsulated organisms - more risk of strep pneumonia (“ humoral immunity” problem)
what do you think of at CD4 counts 200, 100, 50?
200= PCP 100= toxoplasmosis 50= MAC
gram negative coccus that has a prominent polysaccharide capsule and grows on “ chocolate” agar
what do you prescribe as prophylaxis?
Neiserria Meningitidis - see meningitis, petichiae and purpura and can result in loss of digits or extremities
as prophylaxis against this, might be prescribed - rifampin
main SE’s of TB drugs?
INH = liver toxicity eth = visual changes strep = renal and otoxocity pyrazinamide = liver toxicity rifampin = orange urine
ex of obligate intracellular
think chlamydia pneumonia
when is sleep study positive?
5 disturbances of sleep in an hour period
what do you see on EKG with PE’s?
S wave in lead I, Q in lead III, inverted T wave in lead III
(S1, Q3, T3)
Note: sinus tachycardia is probably most commonly seen
h/a with meningitis in AIDS pt?
crytococcosis
CMV
virus seen in AIDS patients of CD4 <50
see owl eye nucelus
pseudohyphae and budding yeast?
candida
H and E stain shows stain shows septate hyphae with acute-angle branching?
aspergillosis - also will see 45 degree angle branching and can form fungus ball
Loeffler’s syndrome
see eosinophilic pneumonia due to a large number of eggs being carried into the lungs by the bloodstream. This can include Trichinella spiralis, Strongyloides stercoralis, Ascaris lumbricoides, the hookworms, and the schistosomes
typical pneumonia?
S. pneumonia, H. influenza, M. catarrhalis - see high fever, rigors cough with sputum and lobar infiltrates
atypical pneumonia?
legionella, mycoplasma, C. pneumonia, viruses - characterized by dry cough and diffuse patchy infiltrate on CXR
whats increased in smokers/COPD?
S. pneumonia, H. influenza, Moraxella, Legionella
alcoholism?
S. pneumonia, anaerobes, TB
D-Dimer
valuable test for negative predictive value in patients with low probably of PE - if its low, you can rule out PE
what is seen with MRSA?
Cavitary infiltrate Rapid pleural effusion Gross hemoptysis Concurrent influenza Neutropenia Erythematous rash Skin pustules Young previously healthy patient Severe pneumonia during summer months
what do you think of in diabetics with absesses?
mucor mucosis
